The invention relates to a wind turbine fault detection circuit and method.
It is known to use current sensors for power converter systems to determine presence of ground faults which may cause loss of power and create safety hazards. A common approach of detecting ground faults of a three-phase power converter is to sum current outputs of the power converter. A desired result would be when the output currents are balanced, i.e. the output currents are 120° out of phase with each other and of equal magnitude, and the output currents cancel each other to result in a summed current value of zero. If, on the other hand, there is a current leak in the power converter, a non-zero reading is recorded at the output of the power converter and this is an indication of a possible ground fault.
However, such a method of detecting ground faults may not be accurate or reliable due to noise created by converter switching that is coupled through a circuit breaker (CB). This noise is usually coupled through stray parameters (stray inductance or capacitance) within or outside the CB.
It is an object of the present invention to provide a wind turbine fault detection circuit and method which addresses at least one of the disadvantages of the prior art and/or to provide the public with a useful choice.